-6.45% is the change from 915 to 856
Calculation steps:
[( 856 - 915 ) ÷ 915] x 100 = -6.45%
Formula
Percentage change = [(856 - 915) / 915] x 100
Subtract the new number by the original number
856 - 915 = -59
-59 ÷ 915 = -0.06448087431693988
-0.06448087431693988 x 100 = -6.45%